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Net::DNS::RR::SIG.3pm

NAME

Net::DNS::RR::SIG - DNS SIG resource record

SYNOPSIS

"use Net::DNS::RR;"

DESCRIPTION

IMPORTANT: For any other use than SIG0 signatures the SIG RR has been deprecated (RFC3755). Use the DNSSIG instead.

All functionality currently remains present although a warning will be printed at first usage of the verify and create methods.

Class for DNS Address (SIG) resource records. In addition to the regular methods in the Net::DNS::RR the Class contains a method to sign RRsets using private keys (create). And a class for verifying signatures over RRsets (verify).

The SIG RR is an implementation of RFC 2931.

SIG0 Support

When Net::DNS::RR::SIG.pm is available the Net::DNS::Packet module will have the abilityh for sig0 support. See Net::DNS::Packet for details.

     my $keypathrsa="Ktest.example.+001+11567.private";
     my $update1 = Net::DNS::Update->new("test.example");
 
     $update1->push("update", Net::DNS::rr_add("foo.test.example 3600 IN A 10.0.0.1"));
     $update1->sign_sig0($keypathrsa);
 
 

METHODS

create

create is an alternative constructor for a SIG RR object.

You are advised to create a packet object and then use the sign_sig0 method to create a sig0 signature.

To create a signature over a packet (SIG0) you can use the following alternative recipe.

     my $keypath= 
             "/home/olaf/keys/Kbla.foo.+001+60114.private";
 
     $sig0 = Net::DNS::RR::SIG->create('', $keypath);
     $packet->push('additional', $sig0) if $sig0;
     $packet->data;  # When the data method on a packet is called
                     # the actual sig0 calculation is done.
 
 

The first argument to the create method should be an empty string in order for the SIG0 magic to work.

The second argument is a string containing the path to a file containing the the private key as generated with dnssec-keygen, a program that commes with the bind distribution.

The third argument is an anonymous hash containing the following possible arguments:

     ( ttl => 3600,                        # TTL 
       sigin =>   20010501010101,          # signature inception
       sigex =>   20010501010101,          # signature expiration
       sigval => 1.5                       # signature validity
       )
 
 

The default for the ttl is 3600 seconds. sigin and sigex need to be specified in the following format 'yyyymmddhhmmss'. The default for sigin is the time of signing.

sigval is the validity of the signature in minutes. If sigval is specified then sigex is ignored. The default for sigval is 5 minutes.

Note that for SIG0 signatures the default sigin is calculated at the moment the object is created, not at the moment that the packet is put on the wire.

Notes:

- Do not change the name of the file generated by dnssec-keygen, the
  create method uses the filename as generated by dnssec-keygen to determine 
  the keyowner, algorithm and the keyid (keytag).

- Only RSA signatures (algorithm 1 and 5) and DSA signatures
  (algorithm 3) have been implemented.

typecovered

     print "typecovered =", $rr->typecovered, "\n"
 
 

Returns the type covered by the sig (should be TYPE000 with common SIG0 usage)

algorithm

     print "algorithm =", $rr->algorithm, "\n"
 
 

Returns the algorithm number used for the signature

sigexpiration

     print "sigexpiration =", $rr->sigexpiration, "\n"
 
 

Returns the expiration date of the signature

siginception

     print "siginception =", $rr->siginception, "\n"
 
 

Returns the date the signature was incepted.

keytag

     print "keytag =", $rr->keytag, "\n"
 
 

Returns the the keytag (key id) of the key the sig was made with. Read ``KeyID Bug in bind.'' below.

signame

     print "signame =", $rr->signame, "\n"
 
 

Returns the name of the public KEY RRs this sig was made with. (Note: the name does not contain a trailing dot.)

sig

     print "sig =", $rr->sig, "\n"
 
 

Returns the base64 representation of the signature.

verify and vrfyerrstr

     my $sigrr=$update1->pop("additional");
     $sigrr->verify($packet, $keyrr) || croak $sigrr->vrfyerrstr;
 
 

If the first argument is a Net::DNS::Packet object and if $sig->type equals zero a a sig0 verification is performed. Note that the signature needs to be 'popped' from the packet before verifying.

Returns 0 on error and sets $sig->vrfyerrstr

Example

    my $sigrr=$packet->pop("additional");
    print $sigrr->vrfyerrstr unless $sigrr1->verify($update1, $keyrr1);
 
 

Remarks

- The code is not optimized for speed whatsoever. It is probably not
  suitable to be used for signing large zones.

TODO

- Clean up the code, it still contains some cruft left from the times that
  the SIG RR was used for signing packets and RR sets.

- If this code is still around by 2030 you have a few years to check
  the proper handling of times...

ACKNOWLEDGMENTS

Andy Vaskys (Network Associates Laboratories) supplied the code for handling RSA with SHA1 (Algorithm 5).

Chris Reinardt for maintianing Net::DNS.

T.J. Mather, <tjmather@tjmather.com>, the Crypt::OpenSSL::DSA maintainer, for his quick responses to bug report and feature requests.

COPYRIGHT

Copyright (c) 2001-2005 RIPE NCC. Author Olaf M. Kolkman <olaf@net-dns.org>

All Rights Reserved

Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of the author not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission.

THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS; IN NO EVENT SHALL AUTHOR BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Based on, and contains, code by Copyright (c) 1997 Michael Fuhr.

This code uses Crypt::OpenSSL which uses the openssl library

SEE ALSO

<http://www.net-dns.org/>

perl(1), Net::DNS, Net::DNS::Resolver, Net::DNS::Packet, Net::DNS::Header, Net::DNS::Question, Net::DNS::RR,Crypt::OpenSSL::RSA,Crypt::OpenSSL::DSA, RFC 2931.